Oh there's reasons to not eat meat, for sure.
Just 2 days ago i restarted eating meat after 5 years not eating any. i'm deficient and am turning to meat as a way to strengthen my body. Long story short, i have a lot of trouble taking care of myself with all the work and stress part and parcel of my life, and i've been getting worse and not better lately, so i decided to turn to meat as a not quite last resort (i'm not dying or anything), but still to stop a slide into ill health. But i like meditating and for spiritual reasons (ie: cultivating my highest consciousness) and for ethical and environmental reasons too I shunned meat-eats for all this time.
Maybe it's because i'm deficient and have been eating too much sugary stuff that isn't any good for my body-mind (thereby lowering my consciousness), but i was surprised how restarting meat eating has not had horrible awful effects on my consciousness that i feared it would. Granted, it's made me a bit sluggish and more 'tamasic' but only for a little while and not when i eat a little bit (of chicken & shrimp, to be precise).
Funny, but i'd say that living in a way over these years that led me into blood deficiency, my clarity and awareness has suffered like i thought it would from eating meat (but for the opposite reason: instead of too much sludge and low-level vibrations, i've just become a tumblweed, ungrounded).
It is said blood is the residence of the shen (meaning that strong blood provides strong roots for the shen/mind, but poor blood means the shen is unrooted, resulting in an ungrounded person).
Now I'm seeing how for some one like me, eating meat when deficient may actually contribute to a better Shen, to higher consciousness, although I still suspect too much meat will dull the mind... so, middle path! (remember how Buddha drank that raw milk?).
Goes to show, extremes are no way to go. They say meat isn't conducive to the spiritual path, but neither is a weakened body.
I'll see where this goes, if I find longer term low dose meat eating has a dulling effect (unless, of course, I'm too dull to notice: Catch 22) and what can be done to lift body mind and consciousness in this modern world of work work work.